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Abstract:

A housing of an exhaust gas treatment component is formed of a material
having the following composition: iron: between 50 and 60 wt. %, nickel:
between 16 and 24 wt. %, chromium: between 15 and 18 wt. %, aluminium:
between 4 and 8 wt. %, and silicon: between 0.5 and 1.5 wt. %.

Claims:

1. A housing of an exhaust gas treatment component, comprising a material
having the following composition:iron: 50 to 60% by weight,nickel: 16 to
24% by weight,chromium: 15 to 18% by weight,aluminum: 4 to 8% by
weight,silicon: 0.5 to 1.5% by weight.

2. The housing according to claim 1, wherein the composition is varied
with regard to at least one of the following constituents:iron: 56 to 58%
by weight,nickel: 18 to 22% by weight,chromium: 16 to 18% by
weight,aluminum: 5 to 7% by weight,silicon: 0.8 to 1.2% by weight.

3. The housing according to claim 1, wherein the composition is varied
with regard to at least one of the following constituents:iron: 56% by
weight,nickel: 20% by weight,chromium: 17% by weight,aluminum: 6% by
weight,silicon: 1% by weight,and wherein a tolerance range of 5% is
permissible with regard to at least one constituent.

4. The housing according to claim 1, wherein said housing has a wall
thickness of less than 1 mm.

5. The housing according to claim 1, wherein said housing has a wall
thickness of less than 0.8 mm.

6. A housing of an exhaust gas treatment component, comprising a material
consisting of the following composition:iron: 50 to 60% by weight,nickel:
16 to 24% by weight,chromium: 15 to 18% by weight,aluminum: 4 to 8% by
weight,silicon: 0.5 to 1.5% by weight.

7. The housing according to claim 6, wherein the composition consists of
the following constituents:iron: 56 to 58% by weight,nickel: 18 to 22% by
weight,chromium: 16 to 18% by weight,aluminum: 5 to 7% by weight,silicon:
0.8 to 1.2% by weight.

8. The housing according to claim 7, wherein the composition consists of
the following constituents:iron: 56% by weight,nickel: 20% by
weight,chromium: 17% by weight,aluminum: 6% by weight,silicon: 1% by
weight,and a tolerance range of 5% by weight is permissible with regard
to at least one constituent.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001]This is a continuing application, under 35 U.S.C. § 120, of
copending international application No. PCT/EP2007/062326, filed Nov. 14,
2007, which designated the United States; this application also claims
the priority, under 35 U.S.C. § 119, of German patent application
No. DE 10 2006 055 879.0, filed Nov. 24, 2006; the prior applications are
herewith incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

[0002]1. Field of the Invention

[0003]The present invention relates to a housing of an exhaust treatment
component such as, for example, a catalytic converter, an adsorber, a
filter, a particle trap. or the like, for use in an exhaust treatment
installation, in particular such an installation in a motor vehicle.

[0004]At present, it is known for both ferritic and austenitic alloys to
be used as a basis for such a housing. Housings of this type must, in
particular, be suitable for having a predefined mechanical strength even
up to temperatures of up to 800° C. and above, in order to ensure
permanent fixing even when the exhaust treatment component is subjected
to considerable dynamic loads.

SUMMARY OF THE INVENTION

[0005]It is accordingly an object of the invention to provide a material
for the housing of an exhaust gas treatment component which overcomes a
variety of disadvantages of the heretofore-known devices of this general
type and which provides a material composition for a housing of an
exhaust treatment component that satisfies the requirements mentioned
above.

[0006]With the foregoing and other objects in view there is provided, in
accordance with the invention, a housing of an exhaust gas treatment
component, comprising a material having the following composition:
[0007]iron: 50 to 60% by weight, [0008]nickel: 16 to 24% by weight,
[0009]chromium: 15 to 18% by weight, [0010]aluminum: 4 to 8% by weight,
[0011]silicon: 0.5 to 1.5% by weight.

[0012]The nickel/aluminum-containing austenitic steel disclosed here has a
relatively high nickel content. This composition is particularly suitable
for receiving metallic and brazed honeycomb bodies since these consist of
a material similar to that of the brazed regions themselves, and an
outstanding oxidation behavior is therefore achieved overall. This
applies in particular when the metallic foils are joined together with a
brazing material which results in a brazing region comprising
approximately 70% nickel, 18% chromium and 10% silicon. Intermetallic
nickel-aluminum precipitations, which greatly increase the mechanical
strength properties at least up to temperatures of approximately
800° C., in particular compared with a simple austenitic steel
material, occur precisely with the composition claimed, and the wall
thickness of the converter shell can therefore be reduced. This
possibility of reducing the wall thickness additionally makes it possible
to provide housings of this type at lower cost and at lower weight, which
are both very desirable.

[0013]Preference is given to a housing in which the composition mentioned
above is varied with regard to at least one of the following
constituents: [0014]iron: 54 to 58% by weight, [0015]nickel: 18 to 22%
by weight, [0016]chromium: 16 to 18% by weight, [0017]aluminum: 5 to 7%
by weight, [0018]silicon: 0.8 to 1.2% by weight.This means, in
particular, that one or at least two of the constituents mentioned is or
are selected in the narrower range.

[0019]Particular preference is given to a housing in which the composition
is varied with regard to at least one of the following constituents:
[0020]iron: 56% by weight, [0021]nickel: 20% by weight, [0022]chromium:
17% by weight, [0023]aluminum: 6% by weight, [0024]silicon: 1% by
weight,wherein a tolerance range of 5% is permissible with regard to at
least one constituent. This means, in particular, that the tolerance
range can vary upward and/or downward about the stated value. The
tolerance range is preferably at most 2% or even at most 0.5%.

[0025]Preference is given to using the housing with a thickness of less
than 1 mm (millimeter), in particular less than 0.8 mm. In this case, the
housing is used, in particular, for receiving a metallic honeycomb body
which is brazed to the housing at high temperature. For this purpose, the
honeycomb body may be constructed with at least partially structured
metallic foils, such that passages, through which the exhaust gas can
flow, are formed. All the foils are preferably brazed (at both ends) to
the housing on the circumferential side.

[0026]Other features which are considered as characteristic for the
invention are set forth in the appended claims.

[0027]Although the invention is illustrated and described herein as
embodied in a component for an exhaust gas treatment system, it is
nevertheless not intended to be limited to the details shown, since
various modifications and structural changes may be made therein without
departing from the spirit of the invention and within the scope and range
of equivalents of the claims.

[0028]The construction of the invention, however, together with additional
objects and advantages thereof will be best understood from the following
description of the specific embodiment when read in connection with the
accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

[0029]The sole FIGURE is a perspective view of a component of an exhaust
gas treatment system.

DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

[0030]Referring now to the figure of the drawing in detail, there is shown
an exhaust treatment component 6 comprising a housing 1 and a honeycomb
body 5, which is positioned in the interior 4 of the housing 1. The
honeycomb body 5 is designed with a plurality of corrugated and smooth
metal foils 7 which are stacked and wound together such as to form
passages 8 through which the exhaust gas can flow. An exhaust treatment
component 6 of this type may be designed, in particular, as a catalyst
support, a mixing element, an adsorber, a particle trap, or the like. In
this case, the housing 1, illustrated here with a cylindrical shape, has
a length 3 and a thickness 2. The thickness 2 is advantageously in a
range of less than 1 mm. In particular, it is less than 0.8 mm.